The present invention relates to semiconductor device technology, and particularly to a technique effective if applied to a semiconductor device having a nonvolatile memory.
Of semiconductor devices each having a nonvolatile memory, there is known one used to store relatively small-capacity information, like information used upon, for example, trimming, relief and image adjustments to an LCD (Liquid Crystal Device), the production number of the semiconductor device, etc.
This type of semiconductor device having the nonvolatile memory has been described in, for example, Japanese Unexamined Patent Publication No. 2001-185633 (patent document 1), which discloses a single level/poly EEPROM configured over a single conductive layer disposed over a semiconductor substrate with being insulated by an insulating layer, wherein the area per bit can be reduced.
A technique capable of causing a nonvolatile memory element formed by a single-layer poly flat technique to enhance a long-term information retention characteristic has been disclosed in, for example, Japanese Unexamined Patent Publication No. 2001-257324 (patent document 2).